An Interferometric Fiber Optic Gyroscope (IFOG), which utilizes counter-propagating electromagnetic waves in a fiber optic coil to sense rotation about the coil, can be susceptible to electronic noise. Such a fiber optic gyroscope uses a bias modulation to bias the gyroscope on a rate sensitivity portion of an interferogram. The bias modulation frequencies can couple into the demodulation circuitry and cause increased bias offset and deadband. For example, any coherent (in phase) noise that presents at the demodulation analog-to-digital converter is a source of error, affecting bias stability, bias offset, and size of gyroscope deadband.
While conventional IFOG electronics adequately filter out power supply noise and internal noise, such IFOG electronics require a grounding scheme with a quiet low impedance chassis ground connection as reference for the power supplies. While this approach works in a gimbaled sphere, where the gyroscopes are rotated using sliprings for power and data transmission, next generation inertial reference systems will not use sliprings, but instead will employ wireless technology for both data and power transmission. This wireless approach removes the chassis (earth) ground connection, and could allow the electronics to be susceptible to noise due to a floating power supply reference.
While it is possible to use separate power supplies for the bias modulation and corresponding demodulation circuitry, this is not practical mostly due to size and power dissipation increases. The size of both the external power supply and the internal circuitry from multiple separated power supplies would be prohibitive. Moreover, the extra power dissipation from multiple power supplies would also be a burden to the normally small system power budget. In addition, requiring an inertial reference system to provide power to the gyroscope with very low ripple voltage is not always practical.